Systems and methods for flushing a cache with modified data

Abstract

Systems and methods for flushing a cache with modified data are disclosed. Responsive to a request to flush data from a cache with modified data to a next level cache that does not include the cache with modified data, the cache with modified data is accessed using an index and a way and an address associated with the index and the way is secured. Using the address, the cache with modified data is accessed a second time and an entry that is associated with the address is retrieved from the cache with modified data. The entry is placed into a location of the next level cache.

We claim: 
     
       1. A method for flushing a cache with modified data, the method comprising:
 responsive to a request to flush data from said cache with modified data to a next level cache, accessing said cache with modified data using an index and a way and securing an address associated with said index and said way and providing said address to said next level cache, wherein said cache with modified data is a cache that maintains data that can be modified by stores that modify the data; 
 using said address, accessing said cache with modified data a second time and retrieving an entry that is associated with said address; and 
 placing said entry into a location of said next level cache. 
 
     
     
       2. The method of  claim 1  wherein data in said cache with modified data is not included in said next level cache. 
     
     
       3. The method of  claim 1  wherein said cache with modified data is a cache that maintains stores. 
     
     
       4. The method of  claim 1  wherein said request to flush data is automatically initiated periodically. 
     
     
       5. The method of  claim 1  wherein said accessing said cache with modified data is facilitated by a probe that couples said cache with modified data and said next level cache. 
     
     
       6. The method of  claim 1  wherein said data is retrieved from said cache with modified data and placed into a location of said next level cache at the pipeline speed of said next level cache. 
     
     
       7. The method of  claim 1  wherein said next level cache is a level two cache. 
     
     
       8. A cache system, comprising:
 a level one cache comprising:
 a store coalescing cache; and 
 a level two cache comprising:
 a cache controller comprising:
 a request accessing component for accessing a request to flush data from a cache with modified data to a next level cache wherein said cache with modified data is a cache that maintains data that can be modified by stores that modify the data; 
 a cache accessing component for accessing said cache with modified data using an index and a way and securing an address associated with said index and said way and subsequently using said address, wherein said address is provided to said next level cache, 
 accessing said cache with modified data a second time and retrieving an entry that is associated with said address; and 
 a writing component for placing said entry into a location of said next level cache. 
 
 
 
 
     
     
       9. The cache system of  claim 8  wherein data in said cache with modified data is not included in said next level cache. 
     
     
       10. The cache system of  claim 8  wherein said cache with modified data is a cache that includes stores. 
     
     
       11. The cache system of  claim 8  wherein said request to flush data is automatically initiated periodically. 
     
     
       12. The cache system of  claim 8  wherein said accessing said cache with modified data is facilitated by a probe that couples said cache with modified data and said next level cache. 
     
     
       13. The cache system of  claim 8  wherein said data is retrieved from said cache with modified data and placed into a location of said next level cache at the pipeline speed of the next level cache. 
     
     
       14. The cache system of  claim 8  wherein said next level cache is a level two cache. 
     
     
       15. A processor, comprising:
 a CPU; and
 a cache system, comprising:
 a level one cache system comprising a store coalescing cache; and 
 a level two cache system comprising:
 a cache controller comprising: 
  a request accessing component for accessing a request to flush data from a cache with modified data to a next level cache wherein said cache with modified data is a cache that maintains data that can be modified by stores that modify the data; 
  a cache accessing component for accessing said cache with modified data using an index and a way and securing an address associated with said index and said way and using said address, wherein said address is provided to said next level cache, 
  accessing said cache with modified data a second time and retrieving an entry that is associated with said address; and 
  a writing component for placing said entry into a location of said next level cache. 
 
 
 
 
     
     
       16. The processor of  claim 15  wherein data in said cache with modified data is not included in said next level cache. 
     
     
       17. The processor of  claim 15  wherein said cache with modified data is a cache that includes stores. 
     
     
       18. The processor of  claim 15  wherein said request to flush data is automatically initiated periodically. 
     
     
       19. The processor of  claim 15  wherein said accessing said cache with modified data is facilitated by a probe that couples said cache with modified data and said next level cache. 
     
     
       20. The processor of  claim 15  wherein said data is retrieved from said cache with modified data and placed into a location of said next level cache at the pipeline speed of the next level cache.